Thermal circuit-closer



H. SIEBEN AND B. c HALDEMAN. THERMAL CIRCULT CLOSER.

APPLICATION FILED JUNE Il, 1917.

Patented May 25, 192()o 'A T To/e/VE Y UNITED STATES PATENT OFFICE.

`HENRY SIEBEN AND BERTRAND C. HALDEMAN, F KANSAS CITY, MISSOURI,ASSIGNORS, BY DIRECT AND MESNE ASSIGNMENTS, T0 CHARLES C. I-IOEFER,

0F KANSAS' CITY, MISSOURI.

THERMAL CIRCUIT-CLOSER.

Specification of Letters Patent.

Patented May 25, 1920.

A To all whom t may concern.'

s Be it known that we, HENRY SIEBEN and BERTRAND C. HALDEMAN, citizensof the United States, residing at Kansas City, in the county of Jacksonand State of Missouri, have invented certain new and useful Improvementsin Thermal Circuit-Closers; and we do declare the followingto be a full,clear, and exact description of the invention, such as will enableothers skilled in the art to which it appertains to make and use thesame, vreference being had to `the accompanying drawings, and to theletters and figures of reference marked thereon, which forma part ofthis specification.

Our invention relates to fusible plugs for electrical connections andmore particularly to a device of that character' for domestic use inconnection with sad irons, cookers, or with other devices utilizingelectric heat or power in such relations that over heating, caused byneglect to disconnect the device v after use might cause damage byscorching or fire, the principal object of the invention being toprovide a plug wherein the electrical circuit is automatically broken ata determined temperature but of suchl mechanical construction that, whenthe `plug has cooled, the parts may be returnedto functional relationwithout replacement of any of' the parts.

MoreV particularly the device comprises ycircuit making and breakingmembers normally yieldably held in functional relation by a fusibleconnection adaptable for fusing lat a determined temperature to permitseparation of the contact makin members and of resetting whenthe circuitis broken to bers separated to show the switch mechan lism and wireconnectlons.

.tion 3.

F ig. III is a longitudinal, central section lrough the plug, o n theline III-III, Fig.

Fig. IV is a transverse section of the same. Y

iFig. V is a sectional view on the line Vf-V, Fig. III.

Fig. VI is a transverse section through the plug on the line VI-VI, Fig.II.

Fig. VII is a perspective view of a modified form of switch actuatingmeans.

Fig. VIII is a detail perspective view of the automatically releasableand resetting parts of the device.

Referring more in detail to the drawings:

1 designates'a plug constructed according to the present inventioncomprising coperating casing sections 2 3 of liber, hard rubber, orother non-conductive material wherein the circuit closing and releasingswitch parts are housed and connections made therewith to the circuitwires and with the device to which the plug is to be applied; thesections 2-3each forming a face of the housing and being held togetherby screws or bolts 4 which extend through coperating projectingneckportions 5-6 at opposite sides of a central body portion 7,Revolubly carried by the housing section I s 2 is a switch controlshaft 10, the inner end of which extends revolubly through the interiorwall 11 of the section 2 and terminates in an interior circular chamber12 in the sec- The opposite end of the shaft eX- tends from the housingthrough an overlying face plate 13 and through a plate 14 that isinterposed between the edge of the section 2 and face plate 13, and isprovided exteriorly of the housing with a turn button 15, whereby the.shaft may be operated to control the switch parts, as will presently bedescribed.

The plate 14y has an extension or lip 14 at its inner end adapted forcontacting the lbody of the iron when the plug is in place to conductheat directly from the iron to the heat controlled element in the plug,so that said element may be affected more quickly and at a lowertemperature than should it be necessary to conduct the heat throughtheentire body of the plug.`

In practice, I prefer to make the plate 14 o f aluminum, as the metal isa good conductor of heat and provides a more sensitive control.

Fixed within the section 3 to the base of the chamber 12 and at pointsdiametrically opposite'the axial line of the shaft 10 are contact plates1G-17, which are adapted to be simultaneously engaged by or disengagedExtended into the housing through an aperture 21, formed by grooves 21',21 in the separate housing members forming the neck portion 5, arecircuit wires 22-22; the wire 22 being attached to the binding post 23on the plate 16 while the wire 22 is extended through the chamber to thebase of the housing where it is attached to one of a pair of socketsleeves 25-25 located within cooperating pockets 26-26 in the oppositesections 2 3 and opening at their base ends to receive contact posts27-27, or the like, on the iron, or other heating member, 28 (Fig. I),and which are the opposite terminals of a heating coil (not shown)located within the iron. The sleeve not connected with the wire 22l isin contact at its inner end with the plate 17 so that with the cross arm18 in functional position a circuit may be completed through the circuitwires, plug and heating unit to heat the iron.

lVound about the portion of the shaft 10, exteriorly of the housing, isa coil spring 30, one end of which is fixed to the shaft and theopposite end to the housing so that the shaft is yieldingly urged tomove the Across arm 18 from contact with the plates 16, 17 in thedirection of the arrow, Fig. Il; movement of the shaft to set oroperative position being limited by a stop ear 3l that is turnedupwardly from the plate 17 to engage one end of the arm, and in theopposite direction after the arm is unseated from the contact plates byan arm 32 on a plate 33 that is fixed to the casing member 2. Rotationof the arm shaft 10 under tension of the spring 3() is prevented, undernormal conditions, by engagement of the tooth 34, of a pawl 35, that ispivotally mount-ed on a pin in the Wall 11 of the housing member 2. Aratchet wheel 3G, that is rotatably mounted on the shaft 10 andcomprises a cup 37 for containing a fusible solder 38 adapted foradherence to the cup and to a plate 39 that is fixed on the shaft 10 andserves as a cover for the cup, the facing sides of the cup and plate 39being preferably separated to receive the solder and effectively connectthe catcher cup with the shaft disk in order that when the ratchet islocked by its pawl, the shaft, 4is held in position to retain the crossarm 18 in Contact with the plates 1G and 17 and thereby maintain aclosed'circuit through the heating member when the plug is on themember, or in position to complete the circuit when not on the member.

lith this arrangement, under normal conditions, the solder forms a unionbetween the ratchet member and shaft which, when the shaft is setagainst tension of thespring, enables the pawl to hold the shaft, butshould the heating unit become over heated to the fusing point of thesolder, the latter will melt and break the connection between theratchet wheel and shaft disk, thereby releasing the shaft so thattension of its spring will throw the shaft around and move the ends ofthe bar 18 off' of its contact plates to break the circuit and therebyprevent excessive heating of the iron that might cause damage to anyarticle with which it might be in contact and a possible conf-lagration.i

To determine whether or not the parts are in connected or disconnectedrelation, we provide the shaft 1() with a pointer 40, preferablyconstituting one end of the spring 3f), that is adapted to register withon and off marks on the face of the housing according to the relativeposition of the switch parts.

lVith the plug containing the heat controlled element separate from theiron or other body, when the iron has reached a temperature sufficientlyhot to melt solder and the current has been automatically cut off,

4the plug may be removed from the iron and,

being a relatively small body, cools quickly so that the contacts may bereset if desired and operation with the iron continued withoutunnecessary delay.

lith this arrangement the iron may be heated to a temperature of 600degrees F. the solder or heat controlled element in the plug adapted tomelt at 15() degrees, and the conductor plate 11 of a resistance tooperatively affect the solder or heat controlled element when the ironoi' other body has reached the determined temperature, so that the lugor the heat controlled element therein does not need to reach thetemperature of the iron before it may opel'- ate.

As the plug cools much more quickly than the iron, it may be repeatedand the iron again put to use much quicker than if it were necessary forthe iron to cool to a temperaperature at which the solder or heatcontrolled element would return to operative condition.

Assuming that the plug is so constructed and that the switch parts are.normally closed as shown in Fig, Il, the plug is applied to the iron,or other device, by seating the plug sleeves 25, 25 over the contactposts 27-27 to close a circuit through the A iron.

It is not the intention that the plug should be left on the iron untilthe fusion takes place, asa primary switch may be used to lcontrol thecircuit, but should the person using the iron forget to turn olf thecircuit, when the iron reaches a certain temperature, heat conductedalong the plate 14, through the ratchet wheel, melts the solder so thatthe shaft 10, being freed and under presisure of the spring 30, it willmove the cross \arm from the contact plates to break the circuit throughthe heating unit.

After the iron vhas become sufficiently cooled the solder sets and theratchet wheel is again locked relative to movement of the shaft and theparts again placed in set position by revolving the shaft against thetension of the spring. I

It will be seen that by so constructing the plug, automatic means isprovided for breaking a circuit to prevent overheating of the iron, orother device, to which the invention is applied.

Having thus described our invention, what we claim as new therein, anddesire to secure by Letters-Patent, is:

l. In an electrical plug connector for electrically heated bodies,contacts adapted to coperate with complementary contacts on the body,means for closing a circuit through the plug contacts and normally urgedto break the contact, a heat-responsive element in the plug normallyopposing the actuation of the circuit closing means to break thecontact, the heat-responsive element being effective to permit thebreaking of the contact when subjectedto a determined heat, member forconducting heat from the heated body to said element.

2. In an electricalv plug connector for heated bodies having contactscoperative with complementary contacts of the heated body, means forclosing acircuit through the plug contacts and normally' urged.'to

' move to open position to break the circuit,

a heat-responsive element normally holding said means in circuit closingposition, and a conducting member for conducting heat from the heatedbody to said device.

3. A circuit closer, adapted to be used o.n

` a heated body, having contact points, `comprising a removable plughaving contacts cooperative` with those of said body, a normally closedswitch in the removable plug for closing a circuit through the plugcontacts, said switch having automatic opening movement in response toheat generated in the heated body and conducted to said plug, and' aconducting member for conducting the heat from the heated body to saidplug. p

4. A circuit closer, adapted to be used on a heated body, having contactpoints, comprising a removable plug having contacts cooperativewiththose of said body, means for closing a circuit through the plugcontacts and normally urged to break the circuit through the contacts, aheat-controlled element in the plug, means operating through theheat-controlled element to set said means, and a conducting member forconducting heat from the heated body to said element. 5. A circuitcloser, adapted to be used on an electrically heated body, havingcontact points, :comprising a plug removable from the body and havingcontact points coperative with those on the body, a movable circuitcloser adapted for closing or opening a contact through said points,means normally urging the circuit closer to open the circuit, anactuator, an element variable under the infiuence of heat, forming aunion between the circuit closer and actuator at a determinedtemperature and changeableto release the circuit closer under a highertemperature but permitting the circuit closer and actuator to beautomatically reunited upon return, of the element to low temperaturecondition, a latch for the actuator op- -erable -to effect setting andholding of the circuit closer, and a heat conductor leading from said'variable element to contact with said body.

tures.

HENRY SIEBEN. p BERTRAND C. HALDEMAN.

In testimonywhereof we affix our signa-

